Nonsquealing bonded brake shoe



Feb. 17, 1953 w. R. RoDGER 2,628,693

NoNsQUEALING Bouman BRAKE sHoE Fil'ed May 16, 1947 JNVENTOR. Milam RRoer BY l Patented Feb. 17, 1953 2,628,693 NONSQUEALING BONDED BRAKESHOE William R. Rodger, Detroit, Mich., assignor to ChryslerCorporation, Highland Park, Mich., a

corporation of Delaware Application May 16, 1947, Serial No. 748,405

4 Claims.

This invention relates to improvements in a brake shoe assembly.

An object of the invention is to provide an improved brake shoe assemblyin which a shoe element and a lining element of friction material aresecured together by an adhesive bonding ma-7 terial in such manner as tominimize objectionable high pitch noise incident to braking engagementof the shoe assembly and the companion brake drum. More particularly,the invention has for an object the provision of such assembly in whichthe elements thereof have registering surfaces and substantially lessthan the Whole of these surfaces are bonded together by an adhesivematerial constituting the sole means for securing the elements one tothe other, the remainder of the registering surfaces being free fromsuch bonding.

Attachment of the lining material to the brake shoe by surface bondingis desirable in that, for example, the lining material may be used untilworn to relatively thin cross-section and no metal-to-metal contactresults from a predetermined Wear of the lining as is the case whenmetallic means is employed in the attachment of the lining material tothe shoe. However, the shoe assembly with the above components securedtogether by bonding the entire area of a lining surface to the shoe hasan objectionable characteristic in that a noise or squeak of arelatively high pitch is Produced when the shoe assembly is forciblyapplied to the associated brake drum to effect a braking action. Suchrelatively high pitch noise is in addition to and to be distinguishedfrom the squeak that may be produced by sudden and forcible applicationof a brake and which may be influenced at least in part by thefrictional characteristics of the lining material.

The aforesaid relatively high pitch noise is believed to be caused byvibration of the brake drum resulting from application ofthe shoeassembly thereto. By bonding less than the entire area of a liningsurface to the shoe, the unbonded section of the lining is relativelyfree to move relative to the bonded section of the lining and therebyabsorb or dissipate some of the energy which would otherwise induce highpitch producing drum'vibrations incident to the forcibleengagement ofthe shoe assembly and drum to -produce braking action.

An illustrative embodiment of the invention is shown in the accompanyingdrawings, in which:

Fig. 1 is an elevational view of a brake shoe assembly embodying theinvention;

Fig. 2 is an enlarged sectional view taken on line 2-2 of Fig. 1;

Fig. 3 is an enlarged fragmentary plan view of the Fig. 1 assembly, aportion of the lining being broken away;

Fig. 4 is a View similar to Fig. 3, but showing a a further embodimentof the spaced bonded areas;

Fig. 5 is a sectional View, similar to Fig. 2, but

(Cl. 18S-234) 2 illustrating a still further arrangement of alternatelyarranged bonded and the lining; Y

Fig. 6 is a side elevational view, partly in section, of a brakingapparatus for a vehicle road wheel and including the improved shoeassembly.

Referring to the drawings, and particularly Fig. 6, a typical vehicleroad wheel braking apparatus includes a drum E rotatable with thevehicle road wheel, a mounting plate 1, and a pair of brake shoeassemblies 8 pivotally secured to thev plate by pins 9 and I0,respectively. The pin 9 for one shoe 8 supports a cylinder II into whichthe non-pivoted end of the other shoe assembly.

extends and the pin l0 for the latter shoe assembly supports a cylinderI2 into which the nonpivoted end of the said one shoe extends. Thecylinder II is typical and contains a piston I3 which is actuated byforcing fluid thereinto, in a direction to cause the associated shoeassembly to engage with the drum 6. The latter rotates in a clockwisedirection as viewed in Fig. 6, when the vehicle is moving forwardly andeach shoe assembly 8 is correspondingly rotated by its piston to engagethe drum and produce a braking action. As is well known in brakingsystems of this type employed in motor vehicles, fiuid is simultaneouslyforced into the cylinder or cylinders of each road wheel from a mastercylinder, the latter forming no particular part of the invention and isomitted for the sake of brevity. In the illustrated two-wheel cylinderarrangement fluid is initially forced into the cylinder II and thence tothe cylinder I2 through a conduit I4. The fluid inlet opening in thecylinder II is indicated at I5. The shoe assemblies 8 are urged bysprings IS in a direction away from the drum 6.

In the illustrated arrangement the shoes rotate in a direction to inducea form of servo-action forY engagement with the drum and in operationeach shoe is equally effective in producing the braking force applied tothe associated wheel.

Referring to Figs 1 to 3, a typical shoe assembly 8 includes an arcuatemetal shoe I6 generally T-shaped in cross section andhaving a web I1provided with an opening I 8 for the pivot pin andv a band I9. A stripof brake lining material 20 is surface bonded to the band' I9 by a lm ofadhesive indicated at 2|. As shown in Figs. 2 and 3, substantially lessthan the entire surface of the lining is adhered to the registeringsurface of the shoe band I9, the adhered area of the lining beingadjacent each longitudinal edge thereof and an area indicated at 22intermediate such adhered areas is not directly secured to the band andis free for limited movementrelatively thereto during application of theassembly 8 to the drum to produce thebraking action. Such relativemovement, as heretofore pointed out, serves to absorb energy which wouldotherwise induce vibration of the drum and produce the high pitch noise.The spaced bonded areas adjacent the lateral edges of the lining 20extend the entire' unbonded areas of 3 length ofthe latter. This lateraledge bonding prevents the edges of the lining turning away from the shoeand eliminates the tendency of such the ready insertion of a toolbetween the band and lining for forcibly removing the latter.

The surface bonding film 2| may be of the ce1- ment type adhesivedisclosed in Saunders and Morrison Patent 2,376,854of May 22, 1945. Theadhesive may be applied tothe surface of the band I9 or the lining 2i)lat the areas selected for bonding, as indicated in the drawings, andthen converted from a solidified unsetl state of a. cured or ,set stateby the application offa curing tempertaure and simultaneouslypressing'the lining and band together. Any `suitable surface bondingadhesive material having the properties necessary for adhering thesurfaces of the shoe and lining elements together may be employed,

Referring to Fig. 4, the lining material 20 is secured to the shoe I6 bya film of cement 2| as in the'previous embodiment, but in thismodification the bonded surface areas are spaced longitudinally of theshoe, that i-s, circumferentially with respect to its arcuate contour.The nonbonded or adhered surface regions are indicated at 23, it beingunderstood that the sections of the lining 20 at the areas 23 are notdirectly secured to the band I9 and are relatively free to move withrespect to the latter to minimize drum vibration as in the mainembodiment. In this form of the invention the longitudinal edges of thelining are bonded to the band I9 only at locations spaced suiiicient toprevent any appreciable upturning of such edges.

Referring to Fig. v5, the embodiment is generally similar to that ofFigs. 1 to 3 in that the lining 20 is adhered at the longitudinal edgesthereof to the-band I9as indicated at 2l. However, instead of therelatively wide unbonded area as in Figs. 1 to 3, there is provided aplurality of alternately arranged bonded areas and unbonded areasintermediate the longitudinal edge bonded areas, the latter beingindicated at 24. Should it be expedient to employ an adhesive requiringa relatively thick coating or film and thus resultingin a substantialspace between the registering surfaces of the band and lining at theunbonded areas, the relatively small lateral dimension of each unbondedarea will minimize any tendency of the lining to deflect at the unbondedareas, particularly immediately adjacent the bondedareas, inresponse topressure between thelining and Yshoe incident toapplication of the sameto the drum.

Although but several specific embodiments of the invention have hereinbeen shown and described, it will be understood that various changes inthe size, shape, and arrangement of parts may be made without departingfrom the. spirit of the invention.

I claim:

1. In a brake shoe assembly of the typeadapted to frictionally engage adrum, a shoe element including an arcuately extending rim, a liningincluding an arcuately extending element of friction material having acentral body of uniform thickness and opposite end portionsand anadhesive material directly bonding areas of concave face at saidendportions and said central body to .the convex face .of said rim,another area of said concave face.. at sadcentral body .beingfree 4 fromVsuch bonding, and theconvex faceI of said central body having an areaoppositethe` bonded area of the concave face of such body adapted toengage the drum.

2. In a brake shoe assembly of the type adapted to frictionally engage adrum, a shoe element including an arcuately extending rim, a liningincluding an arcuately extending element of fric- Ytionvmaterial havinga central body of uniform thickness and opposite end portions, and anadhesive material directly bonding spaced areas o f the concave face ofsaid friction material to the convex face of said rim, each of saidbonded areas extending inwardly from a lateral extremity of said concaveface and continuously length- Wise of said face from one of said endportions to the other thereof, said concave face having an areaintermediate said bonded areas freefrom said bonding, and the convexface of said friction material having areas thereof respectivelyopposite said bonded areas adapted to engage the drum.

3. In a brake shoe assembly of the type adapted to frictionally engage adrum, a shoe element including an arcuately extending rim, a liningincluding an arcuately extending element of friction material having acentral body of uniform thickness and opposite end portions, and anadhesive material directly bonding said rim to areas of the concave faceof the friction material respectively located at said end portions andsaid central body, the last mentioned area 'extending from one lateralextremity of said face to the other such extremity, said face havingother areas free from said bonding, and the convex face of said liningmaterial having an area opposite said last mentioned area adapted toengage the drum.

4. In a brake shoe assembly of the type adapted to frictionally engage adrum, a shoe element including an arcuately extending rim, a liningincluding an arcuately extending body of friction material, the concaveface of said material having a width coextensive with the width of thematerial and presenting a smooth surface throughout its area, and anadhesive material directly bonding spaced areas of said concave face toa face of said rim, said bonded areas extending lengthwise of saidfriction material/and including portions of said concave facerespectively adjacent the lateral extremities thereof, an area of saidconcave face intermediate said bonded areas being free from saidbonding, and the convex face of said firction material having areasrespectively opposite said bonded areas adapted to engage the drum.

WILLIAM R. RODGER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 769,836 Russell Sept. 13, 19041,445,070 Clune Feb. 13,'1923 1,563,368 Hutchinson Dec. 1, 19251,664,855 Gard Apr.v3, 1928 1,947,894 Whitworth Jan. 4, 1929 1,707,515Evans Apr. 2, 1929 1,756,936 Bendix May 6, 1930 .1,812,028 WhitworthJune 30, 1931 1,917,993 Morris July 11, 1933 Y2,376,854 .Saunders May22,1945

